There are many different approaches to the generation of electrical energy which include: 1) using piezoelectric devices to convert vibration into electric energy, 2) converting energy from ocean waves into electric energy, 3) converting coriolis effect into energy, 4) using the electrical response phenomenon of electrostrictive polymers to harvest electrical power from the general movement of objects e.g. human walking motion, 5) converting EM radiation into electrical energy, 6) energy scavengers which adjust their frequency by altering liquid distributions on a beam, 7) collecting acoustic energy and transforming the acoustic energy into electrical energy for use by a sensor, 8) transmitting energy by pressure oscillations in a fluid, and 10) different systems for storing the energy and using the stored energy to power sensors.